Introduce disabling for Touchable* elements

Summary:Introduce a `disabled` property for Touchable* components.

Fix https://github.com/facebook/react-native/issues/2103
Closes https://github.com/facebook/react-native/pull/5931

Differential Revision: D2969790

Pulled By: mkonicek

fb-gh-sync-id: 570a4ff882219f52f2d2ebef3eb73b1df50a0877
shipit-source-id: 570a4ff882219f52f2d2ebef3eb73b1df50a0877

Libraries/Components/Touchable/Touchable.js

@@ -337,7 +337,7 @@ var TouchableMixin = {
    * Must return true to start the process of `Touchable`.
    */
   touchableHandleStartShouldSetResponder: function() {
-    return true;
+    return !this.props.disabled;
   },
 
   /**

Libraries/Components/Touchable/TouchableWithoutFeedback.js

@@ -44,6 +44,10 @@ var TouchableWithoutFeedback = React.createClass({
       React.PropTypes.oneOf(View.AccessibilityTraits),
       React.PropTypes.arrayOf(React.PropTypes.oneOf(View.AccessibilityTraits)),
     ]),
+    /**
+     * If true, disable all interactions for this component.
+     */
+    disabled: React.PropTypes.bool,
     /**
      * Called when the touch is released, but not if cancelled (e.g. by a scroll
      * that steals the responder lock).